Not the best one, but Dawkins’ part was done well.
This is from part of a series.
Filed under: Science | Tagged: Our Place in the Cosmos, Symphony of Science | Leave a comment »
More naturopathy
Posted on November 15, 2009 by Michael
Over at ScienceBlogs, Greg Laden has an excellent post concerning naturopathic medicine. Here he describes one incident of the sort of danger these quack practitioners pose.
The Naturopath treated John with various herbal and homeopathic medicines, and recommended other treatments such as massage. But during the last few months, John had become weaker and weaker, threw up more and more often, and despite a marked increase in the herbal treatments (which, unfortunately, were not particularly homeopathic, and thus not guaranteed to be as harmless as water) John started to lose weight at an alarming rate.
John had a gut obstruction in his small intestines which prevented him from consuming enough food and retaining proper nutrients. This could have been diagnosed and fixed when it first showed up. Instead, John would need emergency surgery. He almost lost his life because of naturopathic ‘medicine’.
Filed under: Science | Tagged: Greg Laden, Naturopathic, Naturopathy | Leave a comment »
Lac Operon
Posted on November 15, 2009 by Michael
The lac operon of E. coli is the classic example for describing inducible prokaryotic gene expression. One excellent video description of it can be found here.
The jist is this. Not all genes are turned on all the time. There are ones which are needed constantly, others which are only needed in specific types of cells, and then others which are ‘turned on’ in specific situations. It is on this last point which I will focus.
In order for a gene to be ‘turned on’, it must be ‘off’ in the first place. All this means is that an organism’s (relevant) DNA is not being transcribed, thus preventing translation and the manifestation of proteins. The way this occurs in E. coli by means of the lac operon is that the lac repressor is bound to a DNA sequence.
A repressor is itself a protein. It binds to an organism’s DNA, thus preventing RNA polymerase from transcribing anything. This is a physical blockade; the repressor prevents the RNA polymerase from physically attaching and running along a specific sequence of DNA. This is the default position for an inducible repressor.
The way the repressor is removed is simple to understand. It has a specific shape to it which enables it to bind to the DNA sequence. However, this shape can be changed if lactose is present. The lactose will bind to the repressor, thus causing an allosteric change in shape. This means the repressor is no longer the specific shape needed to attach to the DNA, so it releases its ‘grip’.
This release allows the RNA polymerase to continue with transcription. This, eventually, turns to translation. In this stage, enzymes are created, two of which are β-galactoside permease and β-galactosidase (there is a third which can be ignored here). The former of the two is membrane-bound. This means it becomes embedded in the cell membrane. This quickens the transport of lactose from outside to inside the cell. Think of it like a tunnel through which only specific shapes can fit.
Once these specific shapes (lactose molecules) pass into the cell, ß-galactosidase breaks them into their constituents, one of which is glucose. This is used as a key source of energy in many organisms, including E. coli.
Once concentration falls, lactose molecules are no longer bound to the repressor, making it free to resume its normal duties attached to DNA.
Filed under: Science | Tagged: e. coli, Lac operon, Repressor | 1 Comment »
Water on the Moon
Posted on November 14, 2009 by Michael
NASA discovered there is plenty of water on the moon.
Experts have long suspected there was water on the moon. So the thrilling discovery announced Friday sent a ripple of hope for a future astronaut outpost in a place that has always seemed barren and inhospitable.
“We found water. And we didn’t find just a little bit. We found a significant amount,” Anthony Colaprete, lead scientist for the mission, told reporters as he held up a white water bucket for emphasis.
He said the 25 gallons of water the lunar crash kicked up was only what scientists could see from the plumes of the impact.
This is equivalent to roughly a bathtub’s worth of water from this double-impact.
One part of me wants to endlessly speculate at the possibility of microbial life. But all reason and rationality tell me to be cautious. Water does not automatically mean life (especially when its frozen).
…but what if it does mean life, at least in this case? Would the world realize the utter significance of this discovery? Not since Darwin described evolution by natural selection has there been such an important find.
Filed under: Astronomy/Cosmology/Physics, News, Science | Tagged: charles darwin, Evolution, Moon, NASA, natural selection, Origins, water | 1 Comment »
The first time I was frustrated by an anti-science stance
Posted on November 10, 2009 by Michael
It was either in preschool or kindergarten that I first learned that the earth was spinning while constantly revolving around the sun. I remember being absolutely fascinated by this. The earth was spinning? It seemed so counter-intuitive. But I had been presented with the facts so convincingly that I never once doubted it to be true. The fact that is also made sense with how night and day, and then seasons, occur iced it for me.
I gleefully took this information home with me. I had a friend living next door and I really couldn’t wait to convey this new information. I had long had a children’s Bible, complete with fun animations, that showed lions and deer and elephants and dogs on an Ark, but that had never excited me. This was different. This was true. I was too young to sift many facts from fiction at that age, but someone had least made a case for a spinning earth; they showed how what they were saying was consistent with real world observations. No one ever bothered to do this for the Ark. Pretty pictures can only go so far.
I finally got home and started telling my friend David all about how earth was spinning and how it rotated around the sun, not the other way around. He was a year younger than I was, so he had apparently yet to come to this lesson. He found my story too incredible to be true. He disputed my account, astutely asking, “If the earth is spinning, why are all the trees standing still? Why aren’t they spinning too?”
I really had no response to this. I had basically been told some facts which were consistent with observation. I didn’t have a full grasp (nay, nary a tenuous grasp) on gravity or anything that would have helped me explain to David why he was wrong. I was only able to repeat what I was convinced was true. This was the first time I had been frustrated by someone taking an anti-science stance. I didn’t know his position was in opposition to science since I was about 5 or 6, but that’s what it was. Fortunately, his position can be excused since he was about the same age. But this raises an interesting question.
What is everyone else’s excuse?
Filed under: Science | Tagged: Science | 4 Comments »
Carl Sagan Day
Posted on November 7, 2009 by Michael
Today is Carl Sagan Day. That means you should appreciate science and have a Cosmos marathon. Also, watch this video. It’s hilarious.
Filed under: Humor, News, Science | Tagged: Carl Sagan, Carl Sagan Day, Carl Sagan Kills Kirk Cameron, Cosmos, Kirk Cameron, Science | Leave a comment »
Naturopathic medicine
Posted on November 4, 2009 by Michael
I just submitted a letter to the local paper concerning another letter they recently published. Here it is.
On 10/29 “Dr.” Christopher Maloney wrote a letter praising Naturopathic medicine. As is so common with charlatans, he was dangerously misleading.Maloney begins by telling us that the regular flu vaccine has no effect on H1N1. He intentionally mentions this piece of irrelevant pedantry because he is setting up his punch-line: flu vaccines only provide 6 to 15 percent protection. This is a lie. Healthy adults face upwards of a 90% reduction in their chance of becoming infected with the flu (CDC). Beyond that, vaccines also dull the intensity of the flu should an individual actually face infection.
For his next dangerous joke, Maloney claims vaccines have no effect on deadly complications in any group. The non-mountebank truth is that they reduce hospitalization in the elderly by 50-60% (CDC). Death rate falls by 80% (CDC).
Next this quack recommends black elderberry for those waiting for a flu shot. PubMed features two peer-reviewed studies to the efficacy of this treatment (and not for the H1N1 virus specifically). It has some positive results, but the researchers note (correctly) that larger studies are needed. It does not, however, “block” the H1N1 virus, as Maloney claims.
Finally, Maloney brings out some false, unsupported statistics about stress. This is nothing more than the usual mantra for alternative medicine supporters.
The most interesting thing about this “doctor” is that he doesn’t mention that Naturopathic “medicine” is actually illegal in two states. Another 30 do not acknowledge it.
His recommendations are borrowed from basic nutritional information at best (and it’s far better to get that from someone with a proper education) and are downright dangerous at worst.
Go to your regular doctor.
On the upside, Maloney is not the swindler Andreas Moritz is. He is a charlatan and a mountebank for all this bunk misleading, but his concern seems to be more genuine and less about money. But he’s still wrong.
In the interest of not making a big, ugly blog post, I will include Maloney’s letter in the comment section.
Filed under: Science | Tagged: Alternative Medicines, Augusta Maine, Christopher Maloney, Naturopathic | 5 Comments »
Naked mole rats and cancer resistance
Posted on October 27, 2009 by Michael
Cells have what is called contact inhibition. This means that once they come into contact with each other (or something else), they will cease to grow (or slow growth significantly). However, this is not true of cancer cells. Indeed, it is a hallmark of such cells; they grow and grow and even layer atop each other. Contact inhibition controls cell growth and cancer is, by one general definition, uncontrolled cellular replication.
A recent study led by Vera Gorbunova of the University of Rochester has focused on the naked mole rat and why it has never been observed to develop cancer.
The findings, presented in The Proceedings of the National Academy of Sciences, show that the mole rat’s cells express a gene called p16 that makes the cells “claustrophobic,” stopping the cells’ proliferation when too many of them crowd together, cutting off runaway growth before it can start. The effect of p16 is so pronounced that when researchers mutated the cells to induce a tumor, the cells’ growth barely changed, whereas regular mouse cells became fully cancerous.
This gene is on top of another gene which contributes to restricted growth. Humans (and other animals) only have one, p27, and it gets ‘worked around’ by cancer commonly enough. Cancer in the naked mole rat is theoretically possible, but since it has to breach two barriers to uncontrolled cellular growth, it is unlikely.
As always, there is an excitement with any discovery which could contribute significantly to curbing or stopping many of the major diseases afflicting humanity, but it must be met with temper.
It’s very early to speculate about the implications, but if the effect of p16 can be simulated in humans we might have a way to halt cancer before it starts,” [says Vera Gorbunova].
Might is the key word, and I think Gorbunova’s caution is appropriate. Cancer is a bit of a devil, to say the least, and every discovery seems to lead to a more complicated understanding of how it works. We’ll see what this research turns out to really mean.
Filed under: Science | Tagged: cancer, Naked mole rats, University of Rochester, Vera Gorbunova | 1 Comment »
Religions would squirm
Posted on October 18, 2009 by Michael
Recent evidence suggests Europa has enough oxygen for life.
The global ocean on Jupiter’s moon Europa contains about twice the liquid water of all the Earth’s oceans combined. New research suggests that there may be plenty of oxygen available in that ocean to support life, a hundred times more oxygen than previously estimated.
The research says various openings in the top of Europa’s massive oceans could provide a pathway for oxidizers to deliver an oxygen content which could quickly exceed that of Earth’s oceans.
All this makes me wonder. What would the religions of the world do? What would they do if life was found elsewhere? I know many would adapt their teachings pretty quickly; they would ignore that a central part of their beliefs is that humans are special (the arrogance!). It may take a period of adjustment, but none of them would let go of what they’ve always believed. They’d just pretend like their holy book was ballparking its claims and move on (just like they do when they claim “days” really means “millions of years”). But what about the other guys? The creationists and likewise country bumpkins? While they tend to be some of the most dishonest people around, I do think they would maintain their point of view. Whereas most of religion would shift uncomfortably for a period, the more literal-minded mooks would squirm. They’d deny facts, twist evidence, make false associations and accusations. I guess I’m basically saying they’d continue exactly what they do now.
Filed under: Astronomy/Cosmology/Physics, Creationism, Religions, Science | Tagged: creationists, Europa, Jupiter, NASA, religion, Richard Greenberg | 1 Comment »
RNAi
Posted on October 15, 2009 by Michael
RNAi is an arrestingly interesting little mechanism for protecting the health of cells. The “i” stands for interference, and with good reason. RNAi is made up of a series of molecules which work to detect and destroy possible viruses and RNA which could be viruses.
It was first detected in 1986 when an attempt was made to make a really, really purple flower. The reason was purely for aesthetics, but it would prove to be far more important.
Knowing the gene which coded for purple pigmentation in petunias, geneticists made the logical conclusion and figured adding a bunch of those genes to the flowers would increase the depth of purple coloring in them. But as it turned out, they were wrong. In fact, they were remarkably wrong. Instead of deep purple flowers, they produced white flowers. Not a hint of purple anywhere.
No one had an answer to why would be. It took 12 years until researchers came up with the answer (and another 8 until they were awarded a Nobel Prize).
When viruses invade a cell, they ‘seek’ to make copies of themselves by utilizing the available DNA source. Post-transcription, this comes out with a funny shape due to the RNA making a mirror image of itself. The RNAi then recognizes this strange shape and destroys it with dicers. But it doesn’t stop there. Any sequence which comes out of the nucleus thereafter is also destroyed. This prevents any of the viruses (hopefully) from being translated and replicating (thus exploding out of the cell and infecting other cells).
Something similar happened when the geneticists tried making the super purple flowers. There wasn’t a mirror-image RNA sequence, but there was a funny sort of shape created by all the extra purple pigmentation genes. The RNAi recognized this as a potential virus and began destroying it. All of it. This meant there were no genes for purple getting translated into proteins.
Example petunia plants in which genes for pigmentation are silenced by RNAi. (http://en.wikipedia.org/wiki/Rnai)
So far this is pretty exciting stuff. It’s a post-transcriptional defense mechanism against viruses no one ever knew existed. But it has so much more potential than just as a passing curiosity.
Think about it. If RNAi can essentially turn off genes by destroying them through a sort of sequence-detection, then what stops it from curing diseases? This discovery has the serious potential to cure all the major ailments facing the world today: AIDS, cancer, Alzheimer’s. There has already been success in treating macular degeneration. This is a disease where too many blood vessels are growing in the eye. It damages the retina over time and makes vision majorly cloudy and blurry. There are simply too many genes for blood vessels being produced. But one way to stop this disease is to stop that blood vessel growth. To achieve this, a patient is given an injection which contains a copy of the gene with its mirror image (two mirror strands of DNA). The RNAi detects this misshape and destroys it. It then destroys all other likewise sequences. The same principle could be applied to any number of diseases.
There is an excellent NOVA video on RNAi which can be viewed here. It’s certainly worth watching (and only 15 minutes long).
Filed under: Science | Tagged: Dicer, DNA, NOVA, PBS, Petunia, RNA, RNAi | 2 Comments »
For the Sake of Science 